2015 United States H5N2 outbreak

In 2015, an outbreak of avian influenza subtype H5N2 was identified in a series of chicken and turkey farming operations in the Midwestern United States. By May 30, more than 43 million birds in 15 states had been destroyed as a result of the outbreak, including nearly 30 million in Iowa alone, the nation's largest egg producer. In the Midwestern U.S., the average price of eggs had increased 120% between April 22 and May 30. The effects however were seen nationwide, with prices in California up 71% in the same timeframe. ^[1]

The virus was first identified in Minnesota in early March. Prior to April 20, it affected commercial turkey farms almost exclusively, in the states of Arkansas, Iowa, Missouri, North Dakota, South Dakota, Wisconsin, and at 28 farms in Minnesota, where the virus was initially identified. ^[2] Migratory waterfowl are assumed to have brought the disease to the Midwest, but how it made its way into poultry barns is undetermined. ^[3]

Spread to hen farms

On Monday, April 20, the U.S. Department of Agriculture announced that 5.3 million egg-producing hens at a northwest Iowa farm must be destroyed after the virus was confirmed. The number at this operation alone comprised a little over 1% of egg-laying hens in the United States. ^[4]

As of May 27, over 25 million chickens had either died of the infection or been euthanized in Iowa alone. ^[5] Nebraska's toll at the same date was 7 million—a majority of the state's 9.45 million egg-laying hens. ^[6]

Table of infections

A map of all poultry killed by the 2015 H5N2 virus or culled to contain the outbreak.

This table shows large bird farm infections during the 2015 outbreak. All birds affected either died of the H5N2 infection itself, or were destroyed as a precautionary measure. While 205 total infections were confirmed through June 1, only larger outbreaks (affecting >200,000 hens or >50,000 turkeys) are displayed here.

Date detected	Location	Birds affected	Type	Source
March 27	Lac qui Parle County, Minnesota	66,000	Turkeys	[7]
April 1	Beadle County, South Dakota	50,600	Turkeys	[7]
April 2	Stearns County, Minnesota	71,000	Turkeys	[7]
April 4	Stearns County, Minnesota	76,000	Turkeys	[7]
April 7	Meeker County, Minnesota	310,000	Turkeys	[7]
April 8	Kingsbury County, South Dakota	71,900	Turkeys	[7]
April 9	Lyon County, Minnesota	66,000	Turkeys	[7]
April 10	McPherson County, South Dakota	55,200	Turkeys	[7]
April 10	McCook County, South Dakota	54,700	Turkeys	[7]
April 11	Jefferson County, Wisconsin	189,100	Chickens	[7]
April 13	Swift County, Minnesota	160,000	Turkeys	[7]
April 13	Stearns County, Minnesota	76,000	Turkeys	[7]
April 14	Swift County, Minnesota	154,000	Turkeys	[7]
April 14	Redwood County, Minnesota	56,000	Turkeys	[7]
April 15	Kandiyohi County, Minnesota	152,000	Turkeys	[7]
April 15	Stearns County, Minnesota	67,000	Turkeys	[7]
April 15	Roberts County, South Dakota	66,600	Turkeys	[7]
April 16	Barron County, Wisconsin	126,700	Turkeys	[7]
April 20	Osceola County, Iowa	3,800,000 [a]	Chickens	[4]
April 20	Wadena County, Minnesota	301,000	Turkeys	[7]
April 20	Kandiyohi County, Minnesota	61,000	Turkeys	[7]
April 21	Kandiyohi County, Minnesota	130,400	Turkeys	[7]
April 21	Kandiyohi County, Minnesota	61,000	Turkeys	[7]
April 21	Stearns County, Minnesota	53,900	Turkeys	[7]
April 22	Stearns County, Minnesota	72,500	Turkeys	[7]
April 22	Kandiyohi County, Minnesota	62,600	Turkeys	[7]
April 22	Kandiyohi County, Minnesota	62,600	Turkeys	[7]
April 22	Meeker County, Minnesota	58,900	Turkeys	[7]
April 23	Clay County, Minnesota	408,500	Chickens	[7]
April 23	Chippewa County, Wisconsin	56,500	Turkeys	[7]
April 23	Kandiyohi County, Minnesota	54,300	Turkeys	[7]
April 24	Jefferson County, Wisconsin	1,031,000	Chickens	[7]
April 24	LaMoure County, North Dakota	71,500	Mixed poultry	[7]
April 24	Kandiyohi County, Minnesota	67,000	Turkeys	[7]
April 24	Chippewa County, Minnesota	64,900	Turkeys	[7]
April 27	Sioux County, Iowa	1,603,900	Chickens	[9]
April 27	Barron County, Wisconsin	83,300	Turkeys	[7]
April 28	Sioux County, Iowa	3,660,000	Chickens	[10]
April 28	Osceola County, Iowa	258,000	Chickens	[10]
April 28	Steele County, Minnesota	82,900	Turkeys	[7]
April 28	Kandiyohi County, Minnesota	50,900	Turkeys	[7]
April 29	Stearns County, Minnesota	202,500	Chickens	[7]
April 30	Buena Vista County, Iowa	449,100	Turkeys	[7]
April 30	Barron County, Minnesota	96,500	Turkeys	[7]
May 1	Buena Vista County, Iowa	4,910,600	Chickens	[7]
May 4	Madison County, Iowa	1,495,600	Chickens	[7]
May 5	Wright County, Iowa	2,821,800	Chickens	[7]
May 5	Nicollet County, Minnesota	1,102,900	Chickens	[7]
May 5	Barron County, Wisconsin	182,400	Turkeys	[7]
May 5	Swift County, Minnesota	151,300	Turkeys	[7]
May 5	Kandiyohi County, Minnesota	89,100	Turkeys	[7]
May 5	Pipestone County, Minnesota	72,200	Turkeys	[7]
May 5	Barron County, Wisconsin	57,200	Turkeys	[7]
May 6	Kandiyohi County, Minnesota	65,000	Turkeys	[7]
May 7	Sioux County, Iowa	309,900	Chickens	[7]
May 7	Osceola County, Iowa	256,000	Chickens	[7]
May 7	Buena Vista County, Iowa	52,900	Turkeys	[7]
May 8	Wright County, Iowa	1,106,500	Chickens	[7]
May 8	Sioux County, Iowa	581,300	Chickens	[11]
May 8	Sioux County, Iowa	327,900	Chickens	[7]
May 8	Sioux County, Iowa	303,100	Chickens	[7]
May 11	Swift County, Minnesota	65,600	Turkeys	[7]
May 12	Dixon County, Nebraska	1,791,500	Chickens	[12]
May 12	Wright County, Iowa	966,600	Chickens	[7]
May 13	Hutchinson County, South Dakota	70,600	Turkeys	[7]
May 13	Yankton County, South Dakota	70,600	Turkeys	[7]
May 14	Lyon County, Iowa	390,000	Chickens	[7]
May 15	Dixon County, Nebraska	1,709,400	Chickens	[13]
May 15	Buena Vista County, Iowa	903,700	Chickens	[14]
May 15	Sioux County, Iowa	272,300	Chickens	[14]
May 15	Sioux County, Iowa	240,000	Chickens	[14]
May 18	Moody County, South Dakota	642,700 [b]	Chickens	[7]
May 18	Meeker County, Minnesota	138,800	Turkeys	[7]
May 19	Renville County, Minnesota	2,045,600	Chickens	[16]
May 20	Sioux County, Iowa	240,000	Chickens	[7]
May 21	Sac County, Iowa	100,000	Turkeys	[7]
May 26	Dixon County, Nebraska	293,200 [c]	Chickens	[7]
May 27	Knox County, Nebraska	3,000,000	Chickens	[6]
May 27	Adair County, Iowa	974,500	Chickens	[7]
May 27	Renville County, Minnesota	95,300	Turkeys	[7]
May 28	Wright County, Iowa	991,500	Chickens	[7]
May 28	Kandiyohi County, Minnesota	50,800	Turkeys	[7]
June 1	Wright County, Iowa	434,800	Chickens	[7]
June 1	Moody County, South Dakota	52,000	Turkeys	[7]

1. Initially reported as 5.3 million birds; APHIS confirmation count was adjusted. ^[8]
2. Originally reported as 1.3 million birds; APHIS confirmation count was adjusted. ^[15]
3. Originally reported as 500,000 birds; APHIS confirmation count was adjusted. ^[17]

Control

When an infection was confirmed, all birds at the affected farm were destroyed per USDA guidelines. The birds were often culled by foam depopulation through pumping an expanding water-based foam into the barn houses, which suffocates them within minutes. The birds were then composted, usually at the location. ^[4]

References

1. Samantha Masunaga (May 30, 2015). "Avian influenza epidemic spurs nationwide rise in egg prices". Los Angeles Times. Archived from the original on April 6, 2020. Retrieved June 1, 2015.
2. "Final Report for the 2014–2015 Outbreak of Highly Pathogenic Avian Influenza (HPAI) in the United States". aphis.usda.gov. United States Department of Agriculture. August 11, 2016. Retrieved July 27, 2024.
3. Robert Roos (May 12, 2015). "Egg farm hit in Nebraska's first H5N2 event". Center for Infectious Disease Research and Policy (University of Minnesota). Archived from the original on July 28, 2015. Retrieved June 2, 2015.
4. "Up to 5.3 million chickens to be destroyed after bird flu confirmed at Iowa farm". Omaha World Herald. April 21, 2015. Archived from the original on July 7, 2018. Retrieved June 1, 2015.
5. Dave Dreeszen (May 27, 2015). "Truckloads of dead birds headed to landfills". Sioux City Journal. Archived from the original on June 9, 2024. Retrieved June 1, 2015. More than 25 million commercial laying hens and pullets in Iowa have been killed by the H5N2 virus or euthanized to prevent the disease from spreading further. One million turkeys also have been destroyed since the first case was confirmed in early April.
6. Richard Piersol (May 27, 2015). "3 million hens to be destroyed on Knox County egg farm". Lincoln Journal Star. Archived from the original on June 30, 2015. Retrieved June 1, 2014. That makes 7 million birds that have been or will be destroyed in Nebraska since bird flu became epidemic in the upper Midwest
7. "Update on Avian Influenza Findings: Poultry Findings Confirmed by USDA's National Veterinary Services Laboratories". United States Department of Agriculture / Animal and Plant Health Inspection Service. June 1, 2015. Archived from the original on September 6, 2015. Retrieved June 3, 2015.
8. Laura Nichols (April 21, 2015). "Here's why killing 3.8M Iowa chickens gets national attention". KCCI News 8 (Des Moines). Archived from the original on July 19, 2015. Retrieved June 3, 2015. The H5N2 virus is highly infectious and deadly, meaning up to 3.8 million hens must be destroyed at Sunrise Farms near Harris in Osceola County. An earlier estimate put the number at 5.3 million.
9. "USDA Confirms More Highly Pathogenic H5N2 Avian Influenza in Three Flocks in Minnesota, Iowa and Wisconsin". APHIS. April 28, 2015. Archived from the original on June 3, 2015. Retrieved June 2, 2015.
10. "USDA Confirms More Highly Pathogenic H5N2 Avian Influenza in 11 Flocks in Minnesota and Iowa". APHIS. April 29, 2015. Archived from the original on June 3, 2015. Retrieved June 2, 2015.
11. "USDA Confirms More Highly Pathogenic H5N2 Avian Influenza in Five Flocks in Iowa". APHIS. May 11, 2015. Archived from the original on June 3, 2015. Retrieved June 2, 2015.
12. Cole Epley; David Hendee (May 12, 2015). "USDA confirms bird flu in northeast Nebraska; flock of 1.7 million chickens to be killed". Omaha World Herald. Archived from the original on June 9, 2024. Retrieved June 2, 2015.
13. Cole Epley (May 14, 2015). "Nebraska officials confirm 2nd bird flu outbreak". Omaha World Herald. Archived from the original on June 9, 2024. Retrieved June 2, 2015.
14. "USDA Confirms More Highly Pathogenic H5N2 Avian Influenza in Five Flocks in Iowa and Nebraska". APHIS. May 18, 2015. Archived from the original on June 3, 2015. Retrieved June 2, 2015.
15. Robert Roos (June 1, 2015). "Avian flu hits four more turkey farms in Midwest". CIDRAP. Archived from the original on June 9, 2024. Retrieved June 2, 2015. The previous outbreak, reported May 14, involved an egg farm with 1.3 million chickens.
16. Liz Sawyer (May 16, 2015). "Renville chicken farm suffers Minnesota's worst bird-flu toll: A Renville operation must destroy 2 million chickens". Star Tribune. Archived from the original on June 3, 2015. Retrieved June 2, 2015.
17. Cole Epley (May 23, 2015). "Nebraska confirms its third case of bird flu". Omaha World Herald. Archived from the original on July 14, 2015. Retrieved June 2, 2015.